The present invention relates to an optical driving device and an optical communication system, and relates to a technique for transmitting laser light modulated in a PAM (Pulse Amplitude Modulation) method, for example.
Japanese Unexamined Patent Application Publication No. 2016-122898 describes a DML (Directly Modulated Laser) driver for PAM. The DML driver includes a current drawing circuit for every bit of a digital input signal, and draws a current corresponding to the digital input signal from a constant current supplied to an LD (Laser Diode) by the current drawing circuit, thereby driving the LD. “25 Gbit/s Optical Transmitter Modules for Optical Transceiver”, SEI Technical Review, No. 186, January 2015, pp. 65-68 describes an optical transmission module with an EA modulator-integrated DFB laser mounted therein. “Compact Optical Transmitter Module with Integrated Optical Multiplexer for 100 Gbit/s”, SEI Technical Review, No. 188, pp. 95-98 describes an optical transmission module with a directly modulated DFB laser mounted therein.